**1. Introduction**

The additive technologies (ATs) (three-dimensional (3D) printing, selective laser sintering/ melting (SLS/M), etc.) are promising techniques for modeling, fabricating of functional graded structures (FGS) with nanoadditives and functional devices, but a direct SLS/M fabrication of the nanopowders by multilayered techniques is a difficult technological task. Laser sintering and melting are known to be thermally activated processes accompanied by the coagulation of nanoparticles into micro-sized conglomerates. However, a real challenge is the aggregation

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

prevention during the 3D printing, which significantly levels the potential advantages of using thematerialsinthenano-orsubmicronstate.Oneofthewaystosolvethisproblemistheisolation of nanoparticles into the inert matrices where they do not undergo any aggregation or "ag‐ ing" and can be controllably released with the retained of chemical and phase composition [1– 3].

Stabilization of nanoparticles in a polymeric matrix and additionally reinforced porous structure makes it possible to arrange a desired distribution of the nanoparticles in the polymer and thus to protect them from agglomeration, oxidation, and corrosion and even to design the FGS. The results indicate that nanoparticles mechanically reinforced the polymer matrix and elastic modulus and the maximum stress significantly increased. Finally, the correlations "prehistory of obtaining (i.e., "background") - chemical composition of the nanoparticles volume and surface condition - phase/structural composition - morphology - perspective properties" will determine the nanoparticles behavior in further applications.

The present review will demonstrate how laser-assisted techniques of the 3D synthesis could be used to prepare a porous core-shell polymer structures containing different encapsulated nanoparticles distributed heterogeneously over the sintered polymer and dangerous for cancer tissue account of thermal hyperthermia or cytotoxic effect. We demonstrated a principal feasibility for fabrication of functionally graded 3D parts with the structural ordering of iron oxide particles and determined corresponding laser optimal regimes. The SLS-fabricated 3D samples of biocompatible iron oxide core/(polyetheretherketone (PEEK) or polycaprolactone (PCL)) shell magnetic nanocomposites have potential medical application for the tissue engineering scaffolds and cell targeting systems [4].

Functionally graded 3D parts with alternating ferromagnetic Ni-PC and nonmagnetic Cu-PC layers [5] exhibited hysteresis phenomena that can probably be used in microelectromechan‐ ical systems (MEMS)-nanoelectromechanical systems (NEMS) applications [6] also, where the time response must depend on the relaxation rate. The synthesized nanocomposites with high porosity and large-specific surface could also find their application in catalysis, lab-on-chips, drug delivery systems, and 3D crystalline structures for hydrogen storage devices [7].


**2. Anesthesia for kidney and upper urinary tract surgery**

#### **2.1. Oncological surgery of kidney and upper urinary tract**

#### *2.1.1. Radical and partial nephrectomy*

Renal cell carcinoma (RCC) is the ninth common cancer in the USA. According to the SEER database analysis, it is estimated that there will be 62,700 new cases and 14,240 people will die because of this disease. The incidence of kidney and renal pelvis cancer was 15.6 per 100,000 in the USA between 2009 and 2013 [5]. All around the world, radical or partial nephrectomy is accepted curative treatment for kidney tumors. Partial nephrectomy can be performed depend‐ ing on the tumor size and localization of tumor. During the partial nephrectomy, localized solid mass must be removed entirely with clear surgical margins [6]. The European Association of Urology (EAU) Renal Cell Cancer Guidelines Panel recommends partial nephrectomy for the tumors less than 4 cm [7].

The flank incision provides advantages in terms of access to the kidney directly, but in case of vena cava involvement, it can be insufficient anatomically. If the tumor size is huge and abdo‐ men exploration or contralateral retroperitoneal exploration is needed, subcostal incision may supply advantages to the surgeon. Various factors including surgeon's experience, tumor size and localization, patient's body habits and localization of affected kidney can affect the inci‐ sion type [8].

#### *2.1.2. Radical nephroureterectomy*

Upper urothelial cell carcinoma is a rare tumor among genitourinary system tumors that con‐ stitute approximately 5% [9]. Radical nephroureterectomy with bladder cuff resections is a standard curative treatment for patients with non‐metastatic upper urothelial cell carcinoma, although advanced developments of minimal invasive surgery and surgical techniques for radical surgery are present [10].

#### *<IP_ADDRESS>. Preoperative considerations*

Known risk factors for RCC include tobacco smoking and be over the age of 60. The peak inci‐ dence of RCC is at the age of 60 years and male‐female ratio is 2:1. Hence, these patients with RCC generally have comorbidities such as coronary‐after‐disease and chronic obstructive pulmonary disease. Only small percent of patients (approximately 10%) have classic diag‐ nostic triad of symptoms including flank pain, hematuria and palpable abdominal mass. Paraneoplastic symptoms and impaired laboratory test including increased erythrocyte sedi‐ mentation rate, eosinophilia and increased hormone levels of prolactin, renin and glucocorti‐ coids [11]. The patient's health status is also optimized by management of anemia, glycemic control and treatment for hypertension, as well as dietary, weight and smoking‐cessation advice before surgery. A consultant‐led, multidisciplinary decision can be made as to which procedure and approach are required for each patient [12]. Because these patients usually have comorbid disease such as advanced age, hypertension, diabetes, chronic obstructive pul‐ monary disease and congestive heart failure and they have had a long and major surgery, it should be appropriate to prepare intensive care bed for these patients to stay in intensive care unit for the critical postoperative period. Intensive care unit can be appropriate to follow up and interfere with postoperative problems that must be treated quickly such as hypother‐ mia, electrolyte imbalance, hemorrhage, infections, pulmonary disorders and requirement of dialysis.

#### *<IP_ADDRESS>. Intraoperative considerations*

During the urological surgery, different complications can develop depending on surgical techniques used. For example, most of urological ventures require lots of irrigation fluids. In this venture, use of unheated irrigation fluid can lead to complications such as hypothermia,

In addition to neuraxial blockade, the use of peripheral blockade has gained importance in uro‐ logical surgery. For example, obturator blockade application for lateral wall localized bladder cancer could reduce intraoperative complications and increased cancer‐free survival [3, 4].

Renal cell carcinoma (RCC) is the ninth common cancer in the USA. According to the SEER database analysis, it is estimated that there will be 62,700 new cases and 14,240 people will die because of this disease. The incidence of kidney and renal pelvis cancer was 15.6 per 100,000 in the USA between 2009 and 2013 [5]. All around the world, radical or partial nephrectomy is accepted curative treatment for kidney tumors. Partial nephrectomy can be performed depend‐ ing on the tumor size and localization of tumor. During the partial nephrectomy, localized solid mass must be removed entirely with clear surgical margins [6]. The European Association of Urology (EAU) Renal Cell Cancer Guidelines Panel recommends partial nephrectomy for the

The flank incision provides advantages in terms of access to the kidney directly, but in case of vena cava involvement, it can be insufficient anatomically. If the tumor size is huge and abdo‐ men exploration or contralateral retroperitoneal exploration is needed, subcostal incision may supply advantages to the surgeon. Various factors including surgeon's experience, tumor size and localization, patient's body habits and localization of affected kidney can affect the inci‐

Upper urothelial cell carcinoma is a rare tumor among genitourinary system tumors that con‐ stitute approximately 5% [9]. Radical nephroureterectomy with bladder cuff resections is a standard curative treatment for patients with non‐metastatic upper urothelial cell carcinoma, although advanced developments of minimal invasive surgery and surgical techniques for

Known risk factors for RCC include tobacco smoking and be over the age of 60. The peak inci‐ dence of RCC is at the age of 60 years and male‐female ratio is 2:1. Hence, these patients with RCC generally have comorbidities such as coronary‐after‐disease and chronic obstructive

**2. Anesthesia for kidney and upper urinary tract surgery**

**2.1. Oncological surgery of kidney and upper urinary tract**

delayed recovery from anesthesia and tremor [2].

*2.1.1. Radical and partial nephrectomy*

54 Current Topics in Anesthesiology

tumors less than 4 cm [7].

*2.1.2. Radical nephroureterectomy*

radical surgery are present [10].

*<IP_ADDRESS>. Preoperative considerations*

sion type [8].

In thoraco‐abdominal approach, since the pleural space is entered, using the noble‐lumen endotracheal tube may facilitate the surgery by deflating the ipsilateral lung. Postoperative ventilation may be needed because of prolonged retraction of the lung that is causing con‐ tusion. During the diaphragm dissection, the phrenic nerve may also be injured by both thoraco‐abdominal incision and flank incision. During operation, excessive blood loss may occur at any stage of operation, which is the reason for the high vascularity of the tumor. Bleeding can be caused by the surrenal gland. At last, adjacent abdominal organs including colon, duodenum and liver may be injured. If the renal mass is on the left side, bleeding due to splenic injury may occur with an incidence as high as 10% [13]. When extensive bleed‐ ing is observed, wide‐channel venous cannulation and central venous cannulation should be obtained for monitoring both the central venous pressure and supply rapid blood transfusion. Prolonged retraction of vena cava may result of transient hypotension. Hence, direct arterial pressure monitoring may facilitate the control of blood pressure, especially in patients with cardiac comorbidity. Moreover, these applications may be helpful for the patients who need mechanic ventilation postoperatively. If the patient has caval obstruction due to naval throm‐ bus, additional management may be needed. Embolization of the tumor fragment may occur during the central venous catheter application, if the thrombus in vena cava extends into the right atrium. When atrial thrombus is observed, a pulmonary artery catheter is contraindi‐ cated. For this reason, many authors suggested that the use of intraoperative transesophageal echocardiography in order to detect tumor extension in the inferior vena cava [14–16].

#### *<IP_ADDRESS>. Choice of anesthesia*

The anesthetic management of patients undergoing radical nephrectomy should include gen‐ eral endotracheal anesthesia. Alternately, combined regional/general endotracheal anesthesia advised to be employed. If the general and epidural anesthesia are combined, epidural cathe‐ ter must be placed and test dose should be administered before the induction of general anes‐

thesia. To perform the induction of general anesthesia after evaluating the effect of the test dose will be reduced the risk of unintended intrathecal and intravascular injection. Although test dose is administered, it would be safer to administer the epidural dose partially and inter‐ mittently. When neuraxial blockade performed, sensorial block level must be Th4. It has been shown that intraoperative epidural infusion of local anesthetic suppresses the stress hormone response and reduces opioid requirement when compared to straight general anesthesia in open nephrectomy [13]. Also, it is advised to reduce pulmonary complications and be more effective to control postoperative pain.

#### *<IP_ADDRESS>. Complications*

Patients with renal failure may be sensitive to benzodiazepines. Cisatracurium may be consid‐ ered for muscle relaxation as it is metabolized via ester hydrolysis and Hofmann elimination. Other pharmacologic considerations for the patient with renal failure include adjusted dosing of antibiotics and avoidance of nonsteroidal anti‐inflammatory agents. Patients with chronic kidney failure have decreased platelet function and von Willebrand factor and reduced red blood cell volume. So the anesthesiologist must transfuse appropriate blood product [17].

#### **2.2. Nononcological surgery of kidney and upper urinary tract**

Nononcological urological surgery of kidney and upper urinary tract includes such proce‐ dures like simple nephrectomy, pyeloplasty, nephrolithotomy or pyelolithotomy, percuta‐ neous nephrolithotomy (PNL), extracorporeal shockwave lithotripsy (ESWL), retrograde intrarenal surgery (RIRS), percutaneous nephrostomy, ureterorenoscopy and ureteral stent replacement. Open stone surgery (nephrolithotomy or pyelolithotomy) is now dramatically reducing and the endoscopic and extracorporeal methods are increasing, overcoat ESWL in those hospitals which has an own lithotripter. Open surgery is actually indicated for the complex renal stone and the complicated ureteral stone [18]. Classically, PNL is done on the patient first in the supine position for replacement of the ureteral catheter and then in a prone position for accessing the caliceal system. Other procedures such as simple nephrectomy, pyeloplasty, nephrolithotomy and pyelolithotomy are performed on the patients in the lateral decubitus position.

#### *2.2.1. Preoperative considerations*

The anesthesiologist should evaluate not only patients' history and physical examination but also existing urinary tract infection. If it exists, antibiotherapy must be given perioperatively. All anticoagulation medications including aspirin and nonsteroidal anti‐inflammatory drugs (NSAIDs) are typically held for 5 days prior to surgery. Blood type and screening are recom‐ mended for the patients who are at high risk of intraoperative bleeding.

#### *2.2.2. Intraoperative considerations*

Antegrade or retrograde ureteropyelography (RPG) is often used to demonstrate the anatomical structure of urinary system or localized the level of urinary system obstruction. Due to the radiographic‐iodinated contrast media used in such PNL procedure, patients have predisposed factors for iodinated contrast media‐related adverse reactions such as a previous adverse reaction to iodinated contrast media, a history of asthma and atopy, dehydration, acute or chronic renal diseases and advanced age, where iodinated contrast media‐induced adverse reactions may observed [19]. The prone position alone for PNL is associated with a variety of position‐related complications. To avoid cervical spine injury during position‐ ing, the head should be held in a neutral position through the turn and positioning. Neck extension or head rotation could also impede carotid and/or vertebral artery blood flow and venous return. The etiology of peripheral nerve injury is usually multifactorial, requir‐ ing both a direct pressure and a stretch component. The large volume of irrigation fluid used during PCNL can decrease body temperature. Hence, monitoring core temperature is routine [2, 20, 21].

#### *2.2.3. Choice of anesthesia*

thesia. To perform the induction of general anesthesia after evaluating the effect of the test dose will be reduced the risk of unintended intrathecal and intravascular injection. Although test dose is administered, it would be safer to administer the epidural dose partially and inter‐ mittently. When neuraxial blockade performed, sensorial block level must be Th4. It has been shown that intraoperative epidural infusion of local anesthetic suppresses the stress hormone response and reduces opioid requirement when compared to straight general anesthesia in open nephrectomy [13]. Also, it is advised to reduce pulmonary complications and be more

Patients with renal failure may be sensitive to benzodiazepines. Cisatracurium may be consid‐ ered for muscle relaxation as it is metabolized via ester hydrolysis and Hofmann elimination. Other pharmacologic considerations for the patient with renal failure include adjusted dosing of antibiotics and avoidance of nonsteroidal anti‐inflammatory agents. Patients with chronic kidney failure have decreased platelet function and von Willebrand factor and reduced red blood cell volume. So the anesthesiologist must transfuse appropriate blood product [17].

Nononcological urological surgery of kidney and upper urinary tract includes such proce‐ dures like simple nephrectomy, pyeloplasty, nephrolithotomy or pyelolithotomy, percuta‐ neous nephrolithotomy (PNL), extracorporeal shockwave lithotripsy (ESWL), retrograde intrarenal surgery (RIRS), percutaneous nephrostomy, ureterorenoscopy and ureteral stent replacement. Open stone surgery (nephrolithotomy or pyelolithotomy) is now dramatically reducing and the endoscopic and extracorporeal methods are increasing, overcoat ESWL in those hospitals which has an own lithotripter. Open surgery is actually indicated for the complex renal stone and the complicated ureteral stone [18]. Classically, PNL is done on the patient first in the supine position for replacement of the ureteral catheter and then in a prone position for accessing the caliceal system. Other procedures such as simple nephrectomy, pyeloplasty, nephrolithotomy and pyelolithotomy are performed on the patients in the lateral

The anesthesiologist should evaluate not only patients' history and physical examination but also existing urinary tract infection. If it exists, antibiotherapy must be given perioperatively. All anticoagulation medications including aspirin and nonsteroidal anti‐inflammatory drugs (NSAIDs) are typically held for 5 days prior to surgery. Blood type and screening are recom‐

Antegrade or retrograde ureteropyelography (RPG) is often used to demonstrate the anatomical structure of urinary system or localized the level of urinary system obstruction. Due to the radiographic‐iodinated contrast media used in such PNL procedure, patients have

mended for the patients who are at high risk of intraoperative bleeding.

**2.2. Nononcological surgery of kidney and upper urinary tract**

effective to control postoperative pain.

*<IP_ADDRESS>. Complications*

56 Current Topics in Anesthesiology

decubitus position.

*2.2.1. Preoperative considerations*

*2.2.2. Intraoperative considerations*

Commonly, general anesthesia with an endotracheal intubation is preferred for simple nephrectomy, pyeloplasty, nephrolithotomy, pyelolithotomy and PNL, although sedation and neuraxial anesthesia for PNL have also been successful [22]. If neuraxial blockade is per‐ formed, the sensorial block level must be Th4.

Recently, anesthetic management of routine ESWL treatments on adults covers effective seda‐ tive and analgesic practice. Different applications could be used successfully such as meperi‐ dine and promethazine, midazolam with alfentanil, fentanyl and ketamine. Substantial research on the use of alfentanil by various routes reported that this drug is very effective [23–25].

#### *2.2.4. Complications*

The major complications during nononcological urological surgery of kidney and upper urinary system tract includes bleeding, bowel and collecting system injury, traumatic arte‐ riovenous fistula or false aneurysm, sepsis, atelectasis, pneumothorax, pleural effusion and hemothorax [26, 27]. As excessive amount of irrigation solution is used intraoperatively in surgical procedures like PCNL, hypothermia is frequently observed. Tekgül and colleagues reported that effects of irrigation solutions, administered at either 21 or 37°C in percutaneous nephrolithotomy (PCNL), on hypothermia and related postoperative complications such as late emergence and late recovery from anesthesia, shivering, lactic acidosis and excess bleed‐ ing [2].


**2. Materials and Methods**

This case study used six in-depth interviews with participants from four garden centers. The six participants (Table 1) were two more than the minimum number needed for a qualitative study as identified by Creswell [29]. The participants at each garden center (Table 2) included the owner and/or the employee most responsible for social-media marketing content. All subjects gave their informed consent for inclusion before they participated in the study. The study was conducted in accordance with the Declaration of Helsinki, and the protocol was approved by the Committee for Research Involving Human Subjects/Institutional Review Board for Kansas State University (project #7183) on 19 May 2014.

**Table 1.** Characteristics of owners and employees at four garden centers in Kansas that were engaged in social-media marketing for their business.

**Table 2.** Characteristics of and marketing channels used by four garden centers in Kansas.

Note: B = blog, E = e-newsletter, F = Facebook, G = Google Plus, H = Houzz, I = Instagram, P = Pinterest, &T=Twitter; engagement rate was calculated on 24 October 2014.

A purposively-selected list of 23 garden centers was generated by a state university Cooperative Extension horticultural specialist with expert knowledge of existing Kansas garden centers. To be included in the list, the garden centers had to be located in Kansas, have exceptional products, good business practices, great customer service, and a presence on Facebook. Since qualitative studies focus on validity and generating a large amount of data from a few participants, the original list of 23 garden centers was scaled down to four garden centers. Two garden centers were selected for a high engagement rate on Facebook and two garden centers were selected that had poor engagement rates. The level of engagement was determined by using Simply Measured's [30] engagement metric which is defined as: engagement rate = (comments + likes + shares)/total number of fans. Simply Measured's [30] engagement rate allows accurate comparisons between Facebook pages. Each of the 23 garden center's previous 60 days' worth of posts were averaged and garden centers were ranked from highest to lowest engagement rate.

Participants were immediately debriefed by the researcher at the end of the interview. Interviews were transcribed by the researcher and a professor's assistant and were entered into NVivo10 (QSR International Pty Ltd., Doncaster, Victoria, Australia) for coding and analysis to determine common linkages and themes. Glaser's [31] constant comparative method assisted the researcher in categorizing participant responses into relevant major themes. Credibility, reliability, and transferability are essential components and concerns of a qualitative study, and the onus is on the researcher to demonstrate the findings result from data and not subjectivities [32]. Shenton [32] also indicates that compromising internal validity is a critical error in qualitative research. In order to mitigate any errors that could decrease credibility, all data was collected and analyzed verbatim with audio recordings and transcribed by the primary author and an assistant. Additionally, after concluding the interview sessions, all participants were debriefed by a researcher to maximize accuracy of the written data as synonymous with participant perception. The research team conducted face-validity analysis of the interview questions to increase validity of the results. External validity in qualitative research is in the eye of the beholder, and it is up to the reader to determine if the information can be generalized to his or her own socially constructed experiences [33].

Although in-depth interviews can yield rich and meaningful data in exploring the experiences of participants, caution should be used in generalizing the findings beyond the specific units of analysis under the specific situations in which they were observed [34]. However, qualitative results may be transferable to other like businesses in similar situations.


**3. Epidemiology of neurological HIV disease**

Studies on the prevalence of HIV among neurologic patients are sparse. The most often quoted study is the CDC study of 195,000 patients in 20 acute-care US hospitals, which found a seroprevalence of 0–13%. This was highly correlated with the seroprevalence among all patients in the hospitals [2]. The study data was difficult to interpret as almost two-thirds of the HIV patients were previously undiagnosed. In a hospital-based study that audited HIV manifestations in medical inpatients in South Africa, the frequency of neurological involvement was 75%, with 11% pure neurological disease, and 64% neurological and non-neurological disease combined [4].

There are several different HIV-1– clades based on phylogenetic data from the diverse HIV strains. Group M ("main") is responsible for the majority of infections worldwide, and is further divided into at least 10 distinct subtypes or clades A, B, C, D, F1, F2, G, H, J, and K. Group O ("out-group") is a relatively rare group currently found in Cameroon, Gabon, and France [6]. The different clades of HIV-1 are not distributed evenly throughout the world. Clade B dominates in North America and Europe. Clade C virus predominates in parts of Sub-Saharan Africa and Asia. Globally, clade C virus is responsible for an estimated 50% of infections and is linked to the rapidly growing epidemics in Sub-Saharan Africa and some parts of Asia,

Neurological Manifestations of HIV

125

http://dx.doi.org/10.5772/intechopen.80054

The effect of the different clades in different populations on the pathological spectrum of HIV infection in these populations is not known. The majority of published data on HIVassociated neurological disease relates mainly to clade B, which is found in North America, Europe, and Australia. Information from regions where clade C dominates is emerging and seems to indicate that there is no effect of the clade on the spectrum of neurological mani-

Aseptic meningitis is a clinicopathological syndrome, and the cardinal symptoms of which are headache, fever, and meningism. Pathologically, it is characterized by serous, nonpyogenic inflammation of the meninges. The defining cerebrospinal fluid (CSF) findings include a mononuclear pleocytosis, normal, or mildly raised protein and normal glucose levels [1]. Aseptic meningitis occurs with an annual incidence rate of 11–27 cases per 100,000 population. The causes are mainly viral infections. Of these, enteroviruses (Echo and Coxsackie) make up 80% of cases followed by mumps, HSV-2, lymphocytic choriomeningitis, and adenovirus. Uncommon causes include infectious mononucleosis, cytomegalovirus (CMV), leptospirosis, HSV-1, mycoplasma, arboviruses (in epidemics mainly in the United States and Europe) and rarely during the icteric phase of infectious hepatitis. In the majority of instances, a causative agent cannot be established (exceptions include enteroviruses, mycoplasma, leptospirosis, and Lyme borreliosis) [1]. The aseptic meningitis in most of these conditions is a self-limiting illness and rarely is of sufficient severity to produce pathological changes in the brain that can

It is important to recognize that an aseptic meningitis syndrome can occur in the course of other infectious and noninfectious inflammatory granulomatous and vasculitic and autoimmune illnesses. This is well described with respect to partially treated bacterial meningitis, so-called neighborhood infections, fungal, mycobacterial, spirochetal, and parasitic meningitis, malignant meningitis, and other noninfectious inflammatory diseases such as sarcoidosis, Behçet's disease, Wegener's granulomatosis, and granulomatous angiitis of the nervous system [1, 2].

mainly in India and China [6, 7].

**4. HIV-associated neurological HIV disease**

be visualized with imaging modalities (CT or MRI).

festations [4].

**4.1. Aseptic meningitis**

*4.1.1. Introduction*

The paucity of this type of data is in stark contrast to established data on the global prevalence of HIV from the Joint United Nations Programme on HIV/AIDS (UNAIDS). In 2016, the WHO estimated that 36.7 million people worldwide are infected with HIV. Sub-Saharan Africa bears the brunt of the HIV epidemic with 25.5 million infected individuals (a prevalence of 6% and 69% of all persons with HIV globally). Asia and the Pacific have 5.1 million infected people, and Latin America has 1.6 million infected people [5].

There are two principal subtypes of HIV, namely HIV-1 and HIV-2:

HIV-1, the predominant subtype is spread worldwide. HIV-2 was found predominantly in West Africa with scattered cases reported in the Americas and Western Europe. Both are associated with the clinical development of progressive immunological impairment with some differences in incubation and transmission properties. HIV-1 is the major cause of AIDS in humans [6].

There are several different HIV-1– clades based on phylogenetic data from the diverse HIV strains. Group M ("main") is responsible for the majority of infections worldwide, and is further divided into at least 10 distinct subtypes or clades A, B, C, D, F1, F2, G, H, J, and K. Group O ("out-group") is a relatively rare group currently found in Cameroon, Gabon, and France [6].

The different clades of HIV-1 are not distributed evenly throughout the world. Clade B dominates in North America and Europe. Clade C virus predominates in parts of Sub-Saharan Africa and Asia. Globally, clade C virus is responsible for an estimated 50% of infections and is linked to the rapidly growing epidemics in Sub-Saharan Africa and some parts of Asia, mainly in India and China [6, 7].

The effect of the different clades in different populations on the pathological spectrum of HIV infection in these populations is not known. The majority of published data on HIVassociated neurological disease relates mainly to clade B, which is found in North America, Europe, and Australia. Information from regions where clade C dominates is emerging and seems to indicate that there is no effect of the clade on the spectrum of neurological manifestations [4].


*3.4.5 Local production and use of biogas*

This technology refers to the production of combustible gas within small-scale digesters at the household level. It is based on the utilization of plant and animal residues as organic wastes that are decomposed in anaerobic tanks, forming methane and a digested slurry byproduct useful as an organic fertilizer and soil amendment [36]. Gasses rise and collect through an outlet for burning as cooking fuel and the sediments sink into sludge for later collection. Gasses may be produced in a variety of vessels located above- or belowground. These reactors may be fashioned from metal tanks, built from concrete, or purchased as complete units. Attraction to this technology is growing across the Sahel because of its socioeconomic and environmental benefits, and it has a proven ability to improve the lives of rural households that would otherwise burn wood and charcoal, or cook using purchased kerosene [5]. The diversification of energy supply creates economic opportunity to those who build and equip these digesters, and it reduces local air pollution and deforestation due to firewood collection and charcoal making, and increases sequestration of carbon into soils amended with the digested organic sludge. Carbon sequestration is also achieved by the substitution of renewable energy production from methane as compared to reliance upon fossil fuels. Biogas generation is best considered among a suite of rural development options that are designed to educate stakeholders and supply the hardware and infrastructure it requires [37].